The goal of this Phase I SBIR is to design, develop, test and validate a rodent behavioral thermal stimulator that allows differential assessment of facial and intra-orally-located nociceptors. Currently no tool is able to perform facial or intra-oral thermal nociceptive mapping in animals or humans. For example, the normal white light radiant thermal stimulus delivered by a projector bulb would provide a too bright visual cue for reliable testing. The well-known Hargreaves plantar foot stimulation device is not fiber type selective and is impractical for use in the trigeminal area. Further understanding of the locations and properties of facial nociceptors is important for probing preclinical models of oro-facial pain and neuropathies and analgesic manipulations directed at the trigeminal system. The development of the infra red laser diode stimulator could lead to a clinical research tool of significant importance for testing sensory abnormalities in patients with oro-facial pain disorders as well as drug validation and discovery. Investigators plan to test the oro-facial area of animals in Phase I. In Phase II, investigators plan to proceed with testing oro-facial areas in normal human volunteers and in patients and developing diagnostic criteria of oro-facial located naturopathic pain. Investigators will design, build and test an oro-facial infra red laser diode thermal stimulator that (A) will deliver collimated light to produce heat in skin, (B) avoid irritation of eyes for humans and animals, (C) allow flexibility in positioning and distance, (D) will have a probe tip that can be used intra-orally as well as on external skin, (E) will enable the user to control the intensity of heat stimuli and selectively activate nociceptive fiber types by controlling light power and pulse duration, and (F) register the reaction response in rodents. [unreadable] [unreadable] [unreadable]